Hi,
I have a stepper/servo motor application that I want to commercialize, and here are the requirements:
1. The stepper motor will be rotating back and forth like a pendalum (180 degree total travel), with a period of roughly 2-3 sec.
2. The torque shall be powerful enough to drive a cassette player.
3. I really prefer not to use Li-ion as it has a dangerous reputation and I want to commercialize something with less risk.
4. I hope the battery can be recharged via a USB cable, rather than using alkaline batteries.
5. Operation should be quiet.
So far, I only found the 28 BYJ48 motor to have the size, cost, availability, torque, and quietness attribute that I need. However, it requires voltage of at least 4V. The drive circuit is simple. Lots of off the shelf drivers uses ULN2003, but I found a more efficient way using MOSFET.
The simplest way would be to use 4 AA batteries to power it. But I hate to have to swap batteries all the time. How do I design the device so that it can be charged via USB like a cell phone?
Maybe I can use a single AA battery, but that'll require a boost circuit which is hard to design. Moreover, the charging circuit is kinda out of my league now too.
Should I just go with the simple approach (4 AA Nimh pack) and commercialize it first? (have a minimal working product), or try to go fancy and go with USB charging? Unless there are off the shelf circuits that'll do the charging and boost the voltage, it'll be too much of a risk from a time and design stand point. Last thing I want is have the device start a fire.
I researched boost circuit, and the best I can do is to buy an IC chip and I still have to design around it. While I'm always up for a challenge, I don't feel it's the best approach from a business stand point.
What is your suggestion?
Thanks